You can use this process when you have to change the plan on the MDNs which have been provisioned and are sitting in inventory, but have not been assigned to any customers yet. This process does not work for changing the plan on the customer’s account.
If you want to change the plan on Active customer’s account then you need to use the process Bulk Customer Plan Change(PC360).
In order to do the Bulk MDN Plan Change you need the following:
MDN: This is going to be the MDN for which you want to change the plan.
Old plan ID: This is going to be the plan which is active on the MDN at present.
New plan ID: This is going to be the plan on which you want to move the MDN.